@Stephen341
It depends on what your objectives are. Do you plan to keep all these reservations? Do you need to cancel them for prepping the house for showings or an open house? When are you planning to list your home - how many months out?
If you cancel the reservations without good cause, you will get penalized by Airbnb on your next payout and the dates will be blocked for future bookings.
If you let Airbnb know you are planning to sell they could advise you on what is best and how to move forward without penalty and potentially cancel your reservations penalty free (I would message the guests to let them know that this is going to happen).
If you let the guests know that unfortunately you have decided to sell your home and would encourage them to find another accommodation and apologize for the inconvenience I think most guests would understand and cancel themselves.
If you plan on keeping the reservations, then I would message them letting them know that you are planning on putting the listing up for sale but this should not impact their stay. They will see a sign for sale in the yard but no one will be touring the property during their stay. If you have good communication with guests and keep them in the loop you shouldn’t have an issue. You also allow them the possibility to find another space if they desire.
Let us know what you decide or find out from speaking with customer service.